1. Field of the Invention
This invention relates to a data recording method and apparatus. More particularly, it relates to a data recording method and apparatus used when doing endless recording especially in a system, such as an AV server used in, for example, a broadcasting station.
2. Description of the Related Art
An AV server system for doing recording, reproduction, editing or distribution of audio video (AV) data is constituted by a data storage device, formed by a hard disc array in which to store the AV data, a plurality of AV data input/output interfaces, referred to below as channels, for data inputting/outputting from the data storage device, and a system controller for managing control of the overall system. Each channel has a memory for making timing adjustments when outputting AV data from the data recording device or inputting data to the data recording device. The AV server system is configured so that the system controller time-divisionally controls the respective channels to permit the AV data to be inputted to or outputted from the data storage device independently from channel to channel.
If such AV server records the materials used in a single program, a variety of different materials are recorded in the AV server. There is a demand for recording certain specified materials and reproducing the latest one, such as a demand for airing an image of the instant of scoring a gall in a soccer game or of the instant of hitting a homer in a baseball game during live broadcast of a sports game.
However, since the hard disc used in the AV server has only a finite recordable area, the conventional practice for meeting above demand is to secure a specified region and data is overwritten in this region by way of endless recording. In case of this endless recording, there is left on the hard disc the data of a pre-set time duration retrogressive from the time of end of the recording at the recording end time.
In the usual endless recording, it may be contemplated to set a recording region on a hard disc and to effect the recording on end only in this region.
During the usual endless recording, it may be an occurrence that certain recording contents are desired to be saved. In the conventional endless recording, data is erased by the recorded contents being sequentially overwritten at an interval of a pre-set time duration. Moreover, since there is a partial stored region, discrete regions on the hard disc have to be accessed in a skipping fashion when reproducing the latest data to render control difficult in the AV server for a broadcasting station in need of real-time processing.
In addition, in saving the designated region in the conventional endless recording, the usual practice is to save the region with an attribute of a file distinct from the file being recorded. Thus, the following problem arises. That is, the region which could be seen on so-called follow-up reproduction of data in the endless recording in another channel cannot be viewed on follow-up reproduction after the processing of partial saving. Therefore, if the user desires to view a saved region after the designation of partial data saving, it is necessary to open a separate file, thus complicating and worsening the efficiency of the processing in the editing operation. There is also a problem that the subsequent retrieval or management is rendered difficult after doing the partial saving a plural number of times.
It is therefore an object of the present invention to provide a data recording method and apparatus whereby part of the recording contents can be saved and editing or management can be performed easily.
In one aspect, the present invention provides a data recording method in which input data from outside are processed by respective ones of a plurality of input processing means and the processed input data are outputted to a non-linear-accessible recording medium only within an allocated time slot so as to be recorded on the recording medium. The data recording method includes a first step of securing a first recording region of the recording medium in which the data is recorded, a second step of sequentially recording the data in the first recording region of the recording medium, a third step of newly securing a second recording region and sequentially recording the data in the second recording region when the data is recorded up to the end position of the first recording region, and a fourth step of sequentially evacuating the oldest recorded region of the first recording region in an amount equal to the second recording region secured in the third step.
In another aspect, the present invention provides a data recording apparatus having a non-linear accessible recording medium and a plurality of input/output processing means for converting data inputted from outside into data recorded on the recording medium, the input/output processing means outputting the data converted within allocated time slots to the recording medium to record the data on the recording medium. The data recording apparatus includes control means for securing a first recording region for repeatedly recording the data on the recording medium and for controlling the input/output processing means and the recording medium so that the data will be sequentially recorded in the first recording region. The control means newly secures a second recording region when the data has been recorded up to the end position in the first recording region. The control means controls the input/output processing means and the recording medium so that the data will be sequentially recorded in the second recording region, while also controlling the input/output processing means and the recording medium so that a recording region of the same volume as the secured and recorded second recording region will be sequentially evacuated beginning from the first region.